ci: adding a non-required check to ensure no existing version on release PR

.github/workflows/versions.yaml

@@ -18,10 +18,21 @@ on:
     branches:
     - main
   pull_request:
-name: unmanaged versions check
+name: versions check
 jobs:
-  check:
+  unmanaged-versions-check:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v3
-    - run: ./generation/check_non_release_please_versions.sh
+    - run: ./generation/check_non_release_please_versions.sh
+
+  # For Release Please pull requests, the artifacts being published must not
+  # have the duplicate versions in Maven Central
+  existing-versions-check:
+    runs-on: ubuntu-latest
+    if: github.repository_owner == 'googleapis' && github.head_ref == 'release-please--branches--main'
+    steps:
+    - run: sudo apt-get update -y
+    - run: sudo apt-get install libxml2-utils
+    - uses: actions/checkout@v3
+    - run: ./generation/check_existing_release_versions.sh

gapic-libraries-bom/pom.xml

@@ -984,7 +984,7 @@
         <version>2.6.1-SNAPSHOT</version><!-- {x-version-update:grafeas:current} -->
       </dependency>
       <dependency>
-          <groupId>com.google.cloud</groupId>
+        <groupId>com.google.cloud</groupId>
         <artifactId>google-cloud-notification</artifactId>
         <version>0.123.22-beta-SNAPSHOT</version><!-- {x-version-update:google-cloud-notification:current} -->
       </dependency>

generation/check_existing_release_versions.sh

@@ -0,0 +1,47 @@
+#!/bin/bash
+
+# Using Google Mirror to avoid unnecessary load to https://repo1.maven.org/maven2
+MAVEN_SITE=https://maven-central.storage-download.googleapis.com/maven2
+
+set -e
+
+function find_existing_version_pom() {  
+  local pom_file=$1
+  if [ -z "${pom_file}" ]; then
+    echo "Empty pom file name"
+    exit 1
+  fi
+  local group_id=$(xmllint --xpath '/*[local-name()="project"]/*[local-name()="groupId"]/text()' \
+      "${pom_file}")
+  local artifact_id=$(xmllint --xpath '/*[local-name()="project"]/*[local-name()="artifactId"]/text()' \
+      "${pom_file}")
+  local version=$(xmllint --xpath '/*[local-name()="project"]/*[local-name()="version"]/text()' \
+      "${pom_file}")
+  echo -n "Checking ${group_id}:${artifact_id}:${version}:"
+  if [ -z "${group_id}" ] || [ -z "${artifact_id}" ] || [ -z "${version}" ]; then
+    echo "Couldn't parse the pom file: $pom_file"
+    exit 1
+  fi
+  if [[ "${version}" == *SNAPSHOT* ]] && [ "${artifact_id}" != "google-cloud-java" ]; then
+    echo " Release Please pull request contains SNAPSHOT version. Please investigate."
+    return_code=1
+  fi
+  local group_id_dir="${group_id//\.//}"
+  local URL="${MAVEN_SITE}/${group_id_dir}/${artifact_id}/${version}/${artifact_id}-${version}.pom"
+  local status_code=$(curl --silent --head -o /dev/null -w "%{http_code}" $URL)
+  if [ "${status_code}" == "404" ]; then
+    echo " The version does not exists. Good"
+  else
+    echo " The version already exists at ${URL}. Please investigate."
+    return_code=1
+  fi
+
+}
+
+return_code=0
+
+for pom_file in $(find . -maxdepth 3 -name pom.xml|sort --dictionary-order); do
+  find_existing_version_pom "${pom_file}"
+done
+
+exit ${return_code}

java-notification/pom.xml

@@ -3,6 +3,7 @@
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
   <modelVersion>4.0.0</modelVersion>
+  <groupId>com.google.cloud</groupId>
   <artifactId>google-cloud-notification</artifactId>
   <version>0.123.22-beta-SNAPSHOT</version><!-- {x-version-update:google-cloud-notification:current} -->
   <packaging>jar</packaging>